David Zilberman, a professor in the Department of Agricultural and Resource Economics, has been awarded the 2019 Wolf Prize in Agriculture. The Wolf Prize is an international award granted by the Wolf Foundation in six categories; the prize Zilberman received is often referred to as the equivalent of a Nobel in agriculture. Zilberman was honored in recognition of his work developing economic models for fundamental problems in agriculture, economics, and policy.

"I am deeply honored to have been selected,” said Zilberman, who holds the Robinson Chair in the Department of Agricultural and Resource Economics. “This prize is a recognition of my entire community: my family, my collaborators, my teachers in Israel and Berkeley, the College of Natural Resources, and the uniquely supportive and inspiring  Berkeley campus."

Zilberman is one of the most cited scholars in agricultural, environmental, and resource economics. During the 1980s, his work served as the basis for several projects on the adoption of modern irrigation technology and computers in California agriculture. These studies demonstrated that farmers adopt new technologies when it makes economic sense and that extreme events, such as droughts or high prices, can trigger changes in farming practices. During the early 1990s, his research on pesticide economics and policy made the case against policies that called to ban pesticides, and advocated instead for smart policies that take advantage of the vast economic benefits that pesticides generate while using incentives to protect against environmental side effects.

In 2014, the California Department of Food and Agriculture reported an alarming discovery: native wildflowers and herbs grown in nurseries and then planted in ecological-restoration sites around California were infected with Phytophthora tentaculata, an exotic plant pathogen that causes root and stem rot.

The presence of this pathogen in restoration sites raised the frightening possibility that ecological restoration, rather than returning disturbed sites to their natural state, may actually be introducing deadly plant pathogens into the wild. New work by a team of scientists in the College of Natural Resources shows just how widespread and harmful the threat of pathogens from restoration nurseries may be.

Led by Matteo Garbelotto, a Cooperative Extension specialist and adjunct professor in the Department of Environmental Science, Policy, and Management, the team surveyed native-plant nurseries in Northern California and found that many harbored Phytophthora pathogens. What’s more, strains of the pathogens from the native-plant nurseries were shown to be at times more aggressive than strains found in the wild, and some of them are rapidly developing resistance to the fungicides that can be used to control them, the researchers found. Results from the team’s work on this topic appeared last December in PLOS One, Plant Pathology, and California Agriculture.

Working with restoration nurseries around the state, the team helped implement new management practices to try to limit the spread of disease without using fungicides. These guidelines, which include careful management of water runoff and soil to avoid cross contamination, reduced the prevalence of disease to nearly zero a year after implementation.

— Kara Manke

When it comes to fuel economy standards, there is no single accepted procedure for arriving at the miles-per-gallon targets that automakers must hit. Rather, analysts use any of multiple parameters and tactics to calculate the potential economic and environmental impacts of fuel efficiency levels.

So when James Sallee, an assistant professor of agricultural and resource economics, first saw that the Obama-era standards had flunked the current administration’s 2018 cost-benefit analysis—which was subsequently used as justification for rolling back the stricter standards—he didn’t think much of it. Analysts had correctly referenced some of his published research findings, and they were working with an ambiguous process.

After digging into the analysis further, however, Sallee went on to co-write, with 10 academic colleagues, a commentary in Science that raises serious questions about the scientific validity of the proposed rule change. That’s because the Environmental Protection Agency and the National Highway Traffic Safety Administration—the agencies that govern fuel standards—arrived at a completely different conclusion from their predecessors’ using exactly the same data.

“So we wanted to know, what’s the difference?” Sallee said. “When we dove into how they changed the model, we disagreed with almost all of the ways the major changes were implemented.” The team uncovered mistakes in math and in the application of economic theory.

Because of errors like those as well as other actions—such as the abandonment of the Paris Agreement and the Clean Power Plan—Sallee noted, scientists are increasingly concerned about a perceived sidelining of science in the Trump administration’s decision-making processes. “It’s unambiguously distressing. In the long run, that’s the biggest concern, rather than any individual policy.”

Sallee said that the real litmus test will be whether federal analysts address the errors. If they don’t, he added, the Science article forms part of a “trail of concern”—formal scientific objections that could potentially be used by future leadership to revoke the current policy decisions.

— Anne Brody Guy